proc

[Cory Wright] shares a tip on how to reboot a system with a failed hard drive remotely. The magic SysRq key is a linux kernel feature that lets you perform a number of interesting operations. If you’re working on a remote system where the disk has failed, you won’t have access to the reboot or shutdown commands. You can issue keystrokes to the magic SysRq device in /proc though, so you can send a hard reboot directly to the kernel with no disk access required.